Flat bottom paper container



Jan. 31, 1961 H. c. BEI-:RENS

FLAT BOTTOM PAPER CONTAINER Filed oct. 31, 195e nited States Patent O i FLAT BOTIOM PAPER CONTAINER Herbert C. Behrens, Easton, Pa., assignor, by mesne assignments, to American Can Company, New York, N.Y., a corporation of New Jersey Filed Oct. 31, 1956, Ser. No. 619,552

2 Claims. (Cl. 229-15) This invention relates to improvements in a fiat bottom paper or thermoplastic container, and more particularly to a paper container that may be utilized for the serving of hot or cold drinks, packaging various types of hot or cold food commodities, and for various other purposes as will be apparent to one skilled in the art.

In the manufacture of containers made of paper or thermoplastic sheet material and including a rolled body part having overlapping marginal portions forming a side seam extreme difficulty has been experienced in the past in an endeavor to effectively seal the container against leakage at the so-called X-point. This so-called X- point occurs where the outer lap of the side seam passes over the edge of the inner lap, and at that point a slight opening occurs with the body part wrapped around a bottom blank, and extra care and caution had to be taken to effect a proper seal at that particular location to prevent leakage when the cup was in use. That was particularly true in connection with cups made for the purpose of serving hot drinks, because a hot drink has more adverse effect on such a cup insofar as possible leakage is concerned than does a cold liquid or commodity. In the making of a flat bottom cup, it is customary to fold under the lower margin of the body part of the cup and engage the folded margin with the bottom blank. Heretofore, in order for leakage to occur liquid had to percolate through the X-point and then only the distance of the width of the folded margin, and since the overlap was equally as present in the folded margin as in the side seam, avoidance of leakage at that particular location required an objectionable amount of care.

Further, with cups of this character heretofore known, the bottom blank was skirted; i.e. a substantially cylindrical flange extended either upwardly or downwardly from the bottom blank. If that ange extended downwardly, the marginal portion of the body was turned inwardly and upwardly into engagement with the flange. If the flange extended upwardly, the marginal portion of the body was turned inwardly and upwardly beneath the at bottom of the cup. Special sealing tools had to be employed in order to effect the proper seal at that point, and the resultant cup had a bottom a substantial distance upward from the lower end of the side wall, so that in some localities the cups were subject to charges of false packaging i-n that the cup was not filled the full length of the body part.

In addition, it may be mentioned that extreme difficulty was also experienced in providing fiat bottom paper cups that were easily dispensed accurately one at a time, and yet when nested had the rolled rim beads of the cup in contact with each other. In other words, if the rim beads were in contact the cups were wedged, and most frequently the rim beads were materially separated by virtue of bottom contact of adjacent nested cups. With the rim beads separated a lesser quantity of nested cups could be placed in automatic cup dispensing machines than if the rim beads actually contacted. It is highly important in the case of automatic vending machines, whererice in both the cup and the drink is dispensed, that there be as many cups as possible in each stack of nested cups, so that servicing of the machines is reduced.

With the foregoing in mind, it is an important object of the instant invention to provide a container wherein the X-point has been sealed in a simple, economical, and positive manner.

Another object of the instant invention is the provision of a flat bottom paper container wherein the X-point is sealed as effectively as any other part of the container.

A further feature of the instant invention resides in the provision of a flat bottom paper container wherein the bottom is substantially what may be termed a flush bottom whereby the container may be filled substantially the entire length of the side wall.

It is also a feature of this invention to provide a flat bottom paper cup which may readily be nested with like cups in a stack, and wherein the cups are maintained separated in the stack solely by contact of the rolled rim beads at the mouth ends of the cups.

It is also an object of this invention to provide a flat bottom paper cup having a side wall with overlapping marginal portions forming a side seam, and with the lower margin of the side wall turned under a bottom blank and secured thereto, the outer lap of the side seam extending farther beneath the cup bottom than the inner lap to effectively seal off the X-point.

Still a further object of the invention resides in the provision of a flat bottom paper container embodying a side wall, and a skirtless bottom, the lower margin of the side wall, being turned under the bottom and secured thereto, and the underturned margin being provided with a series of annular grooves to enhance the securement.

Still another object of this invention resides in the provision of a flat bottom paper cup having a side seam formed by overlapping portions of the body part of the cup, a skirtless bottom, and with the lower margin of the body part turned under the bottom and heat sealed thereto, the outer lap of the side seam extending further under the bottom than the inner lap, and the underturned margin being prov.ded with a series of grooves to enhance the heat seal with at least one of those grooves in the extended portion of the outer lap.

While some of the more salient features, characteristics and advantages of the instant invention have been above pointed out, others will become apparent from the following disclosures, taken in conjunction with the accompanying drawings, in which Figure l is a side elevational view of a flat bottom paper -cup embodying principles of the instant invention;

Figure 2 is a greatly enlarged fragmentary plan sectional view taken through the side seam of the cup body;

Figure 3 is also a fragmentary enlarged vertical sectional view through the bottom portion of the cup taken substantially as indicated by the line III-III of Figure 2, looking in the direction of the arrows;

Figure 4 is a fragmentary bottom plan view of the structure of Figure 2;

Figure 5 is a fragmentary enlarged vertical sectional view taken substantially as indicated by the lline V-V of Figure 2; and

Figure 6 is an elevational View, with parts broken away, illustrating a stack of nested containers.

As shown on the drawings:

In the illustrated embodiment of the instant invention there is shown a flat bottom paper cup comprising a side wall or body part 1 which is preferably made from a single blank of material rolled into the proper shape with overlapping marginal portions 2 and 3 forming a side seam. Preferably the body blank is made of paper treated as may be desired, and provided with a thermoplastic lining which may be either sprayed thereon or provided in sheet form, as may be most desirable. With the thermoplastic lining, the overlapping marginal portions 2 and 3 may be heat sealed together. Without a thermoplastic lining, these overlapping marginal portions would be glued together. However, with the lining a single-wall cup may be utilized for the serving ofY hot drinks, whereas in the past it was necessary to have a double-Wrap or double-wall cup in order to properly handle hot liquids. Of course, the thermoplastic lining is such that has a melting point higher than the boiling point of the liquids commonly served in cups of this character, such as coffee, tea, hot milk, etc.

A bottom 4 is provided for the cup, and this bottom is; merely inthe formofa disc having thecentral portion thereof slightly elevated as indicated at 5 in Figure 5, the elevationl being preferably substantially the thicknessv` of the` paperforming the bottom. This slight elevationA is provided in order to give the finished cup adequate stability so that it will rest around the margin of the bottom rather than over the entire bottom. Further, itewill be noted that the bottom outside of the slightY cen,- tral elevation is flat and skirtless.

In the manufacture of the cup, thelower margin of the sidewall ory body'part isv folded or turned under the bottom 4;.. The margin 6 of the bottom outside the annular offset 5 is contacted on its underface by the underturned margin 7 of the side wall or body part 1. Of course, the underturned marginal portion 7 is secured to the bottom, and if the body blank of the container contains the thermoplastic lining, the underturned margin 7 may be heat sealed to the bottom. The heat sealing operation for attaching the underturned marginV to the bottom may be performed at the same time as the overlaps 2 and 3 are secured togetherto form the side seam onthe body-part, In the finished container, therefore, there` will be sub.- st-antially a flush bottom, with the offset central portion 4 of the actual bottom insuring that the cup rests upon the underturned margin 7 so as tol be stable when filled. Theshowing in Figure 5 is somewhat exaggerated for purposes of clarity and actually the margin, 7 will appear atter and bemore compressed than illustratedin this figure. Thus, the cup may belled to substantially the entire I Gllgthpf the` sidewall and any charges offalse packaging invarious territories are eliminated.

The so-called X-point where leakage is most apt to occur in a container of this character has been designated Xin. Figures 2 and 3, this point being where the outer overlap 2 extends over the edge of the inner lap 3 on the side, seam. Of course, the X-point will not be all along the side seam, but only where the underturned marginal portion 7 passes around the circumferential edge of the bottom.` In order to insure adequate sealing at that point, the blank forming the body part of the instant container is` provided with an extension 8 on the underturned portionZa of the outer lap 2 ofthe side seam, which, as seen clearly in Figures 2, 3 and 5, extends inwardly beyond the termination edge of the underturned portion 3a of the inner lap 3. It will also be noted from the showing in Figures 2 and 4, that this extension 8 extends circumferentially an adequate distance to either side of the edge of the inner lap 3. Therefore, if liquid tended to leak through the X-point, it would not only have to travel the width of the underturned margin 7, but would also have to travel lengthwise the length of the overlap 8' in either direction, and that is substantially impossible. From the showing in Figure 5, it will be noted that the overlap extension 8 contacts a marginalV portion ofthe bottombeyond the termination of'the portion 3a of the inner lap of the side seam. This extension 8 is heat sealed .4 to the bottom beyond the inner lap of the side seam, and the entire underturned margin is preferably provided with a series of annular grooves 9 die pressed at the time the heat seal is made to insure a positive seal, and at least one of these grooves as seen in Figures 4 and 5 is on the extension 8,

The container is also provided with a rolled rim bead 10 around the. mouth end. thereof, and. this rim bead is preferably so sized that when the containers are stacked in nested relationship as-seen in Figure` 6, the rim beads are in contact with each other and maintain the bottoms of adjacent cups out of' contact. Accordingly, the cups may be freely dispensed accurately one at a time since there is nothing binding the cups together. With such construction, it is possible tov place. more cups in a stack of nested cups and thus lessen the time of servicing for automatic beverage dispensing machines and other types ofA dispensers..

From the foregoing, it is apparent that I have provided anreconomical, substantially Hush-bottom paper container highly suitable` for hot or cold drinks and commodities, andinwhich a positive seal is readily and economically acquired at all points` It will b e understood that modifications and variations may.I be, further etfectedwithout departing, from the scope of the novel concepts of the present invention.

I Claim as my invention:

1. A hat bottom paper cup, comprising a body part formed from a rolled blank; having overlapping marginal portions forming a side seam, a skirtless bottom, the lower margin ofthe body part being folded under said bottom and' secured' thereto, andthe outer overlapping lower margrina'l` portion o f said body part having an extension on the bottom edge thereof reaching on both sides of the free edge of' the inner overlapped lower marginal portion and extending farther beneath said bottom than the bottom edge ofthe inner lower marginal portion, said extension being secured directly to the bottom, whereby to prevent leakage past the-bottom end of the seam.

2; A hat bottom paper cup, comprising a body part formed from a rolled blank: having overlapping marginal portions forming a sid'e seam, a skirtless bottom, the lower margin off the body-part being folded under said bottoml and' secured thereto, and the outer overlapping lower marginallportion-of said bodypart having an extensionon thebottom edge thereof reaching on both sides oi the free edge of the inner-overlapped lower marginal portion and` extendingv farther beneath said bottom than thebottomedge 'offthe inner-lower marginal portion, said extension being secured directlyfto the bottom, said folded under lowermargin oftherbody part havinga series of annular-grooves pressed thereinatv least one of which is in said-1 extension beyond the lower inner marginal portiony to provide'la securely sealed seam between said extension andsaid bottom.

References Cited' in thele of this patent UNITED STATES PATENTS 

